This is a looping playback of a 1080p clip (Candle project) with noise reduction added and rendering on the fly. The graph displays the results using OpenCL which was faster than Metal, in this case. (HIGHER frames per second = FASTER)

This is a looping playback of a 3840x2160 RED (R3D) clip. (HIGHER frames per second = FASTER)

Motion

We performed a Render RAM Preview of the Atmospheric sample project. We calculated frames per second. (HIGHER Frames per Second = FASTER)

Final Cut Pro

We used the BruceX sample project to create a ProRes 4444 XQ 5120x2700 Master File. (LOWER Time in Seconds = FASTER)

Compressor

We had FCPX send the BruceX project to Compressor to create a Apple Device HEVC 10-bit version. (LOWER Time in Seconds = FASTER)

PhotoZoom

We took a 66.67 x 50 inch image and upscaled it by 400%. (LOWER Time in Seconds = FASTER)

DaVinci Resolve, Motion, and PhotoZoom appeared to benefit most from the presence of a eGPU with either the AMD RX 570 or RX Vega 56 GPU.

Notice that the 'indirect' setup (using the LG UltraFine 5K display directly connected to the mini's TB3 port and the eGPU connected to a second TB3 port) produced the best performance for Motion, FCPX, and DaVinci's Deliver. (You should select "Prefer External GPU" in the Get Info panel for each app or the app is likely to ignore the eGPU. Some apps like DaVinci 'see' all GPUs and even let you choose the one you wish to use. You can even specify Metal or OpenCL as the rendering method.)

Handbrake is an example of an app that IGNORES the GPU. So adding an eGPU will NOT speed up its transcoding time.

Though the Mac mini Core i5 had only 8G of memory, the only test app that starved was Motion (which requires 10G to itself to load our 600 frame sample). We compensated by calculating FPS to preview the 311 frames the mini was able to load with 8G of memory. For pro apps, it would be wise configure your Mac with at least 16G of memory. More would be advised if you are multi-tasking with pro apps.